U.S. patent number 5,289,072 [Application Number 07/910,345] was granted by the patent office on 1994-02-22 for electrical machine.
This patent grant is currently assigned to J. M. Voith GmbH. Invention is credited to Andreas Lange.
United States Patent |
5,289,072 |
Lange |
February 22, 1994 |
Electrical machine
Abstract
A current rectifier-excited synchronous electrical machine
includes a rotor defining an axis of rotation. The rotor includes a
rotor shaft, a stator housing, and a central disk. The rotor shaft
is mounted in the stator housing. The central disk extends radially
outward from the rotor and defines an outer circumference. At least
one ring-shaped pole structure is secured to the disk outer
circumference and disposed coaxial to the axis of rotation. The
pole structure includes a plurality of permanent magnets, soft iron
elements and insulators. The permanent magnets and soft iron
elements are disposed in interleaved fashion. The insulators are
formed of magnetically and electrically nonconductive material and
are disposed between each of the magnets and iron elements. The
magnets, iron elements and insulators are disposed in two
side-by-side rows. Each pole structure is opposed by a stator
assembly comprising an outside stator and an inside stator. The
outside stator is disposed radially outward of the pole structure,
and the inside stator is disposed radially inward of the pole
structure. The outside and inside stators are armature elements of
a general U-shape defining a pair of ends disposed adjacent and
facing the pole structure. A single armature winding operably
excites the stator. The armature winding is disposed only in one of
the outside stator and inside stator, and the other of the outside
and inside stator is void of a winding.
Inventors: |
Lange; Andreas (Heidenheim,
DE) |
Assignee: |
J. M. Voith GmbH (Heidenheim,
DE)
|
Family
ID: |
6418756 |
Appl.
No.: |
07/910,345 |
Filed: |
September 30, 1992 |
PCT
Filed: |
October 15, 1991 |
PCT No.: |
PCT/EP91/01955 |
371
Date: |
September 30, 1992 |
102(e)
Date: |
September 30, 1992 |
PCT
Pub. No.: |
WO92/10023 |
PCT
Pub. Date: |
June 11, 1992 |
Foreign Application Priority Data
|
|
|
|
|
Nov 23, 1990 [DE] |
|
|
4037231 |
|
Current U.S.
Class: |
310/266;
310/156.02; 310/179; 310/162; 310/45; 310/112; 310/409;
310/216.023 |
Current CPC
Class: |
H02K
21/125 (20130101); H02K 2201/12 (20130101) |
Current International
Class: |
H02K
21/12 (20060101); H02K 001/22 () |
Field of
Search: |
;310/166,156,162,163,45,112,179,254,261,216 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
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|
|
|
|
0356368 |
|
Feb 1990 |
|
EP |
|
3536538 |
|
Apr 1987 |
|
DE |
|
3705089C2 |
|
Feb 1989 |
|
DE |
|
Primary Examiner: Skudy; R.
Attorney, Agent or Firm: Baker & Daniels
Claims
I claim:
1. A current rectifier-excited synchronous electrical machine,
comprising:
a rotor defining an axis of rotation, said rotor including a rotor
shaft, a stator housing, and a central disk, said rotor shaft
mounted in said housing, said central disk extending radially
outward from said rotor and defining an outer circumference,
at least one ring-shaped pole structure secured to said disk outer
circumference and disposed coaxial to said axis of rotation, said
pole structure including a plurality of permanent magnets, soft
iron elements and insulators, said permanent magnets and soft iron
elements disposed in interleaved fashion, said insulators formed of
magnetically and electrically nonconductive material and disposed
between each of said magnets and iron elements, said magnets, iron
elements and insulators disposed in two side-by-side rows;
each said pole structure opposed by a stator assembly comprising an
outside stator and an inside stator, said outside stator disposed
radially outward of said pole structure, said inside stator
disposed radially inward of said pole structure, said outside and
inside stators comprising armature elements of a general U-shape
defining a pair of ends disposed adjacent and facing said pole
structure; and
a single armature winding for operably exciting said stator, said
armature winding disposed only in one of said outside stator and
inside stator, the other of said outside and inside stator being
void of an armature winding.
2. The electrical machine of claim 1, wherein said armature winding
is disposed in said outside stator.
3. The electrical machine of claim 1, wherein said stator void of a
winding is formed with laminated back circuit elements defining
C-cores, said stator void of a winding disposed in a peripheral
direction with a spacing corresponding to two times the pole pitch
of the rotor.
4. The electrical machine of claim 1 wherein said stator having
said armature winding disposed therein comprises a row of U-shaped
C-cores, said C-cores extending in a peripheral direction and
disposed around three sides of said armature winding.
5. The electrical machine of claim 1 comprising two pole structures
and two stator assemblies, said outside stator and inside stator,
and each of said stator assemblies including said armature winding,
each said pole structure and stator assembly respectively disposed
axially symmetrically on each side of said central disk, said
armature disposed in either of said inside stator and outside
stator.
Description
BACKGROUND OF THE INVENTION
The invention concerns an electrical machine, specifically a
rectifier-energized synchronous machine on the transversal flow
principle. A machine designed according to this operating principle
is known from DE-PS 37 05 089.
The so-called transversal flow concept is based on exciting the
stator field not in the longitudinal direction of the
machine--i.e., parallel to the axis of rotation of the rotor--but
in peripheral direction, that is, along the direction of movement
as the rotor rotates. To that end, the rotor has at least a pole
structure of two side-by-side rows of permanent magnets alternately
magnetized in peripheral direction and soft iron elements, the two
rows being separated by an intermediate layer of magnetically and
electrically nonconductive material. In principle, this pole
structure is of drum shape.
The stator consists essentially of two parts, namely an outer
stator arranged radially outside the pole structure and an inside
stator arranged radially within the pole structure. Each stator
part features soft iron armature elements which essentially are
fashioned U-shaped and whose open shanks are opposed in magnets of
the rotors, from radially inside or radially outside, across an air
gap. The prior machine features for excitation, for each stator
part, an annular winding extending in peripheral direction.
With this arrangement characterized by a simple winding structure
and with a direction of magnetic flux extending transverse to the
direction of movement, high power densities can be achieved,
especially when selecting small pole pitches. The electrical lead
to the two annular windings of the stator halves must be passed
through the armature elements. For removal of the heat accuring in
the windings there are as well only the spaces between the armature
elements available. On the inside stator, however, the spaces
between the armature elements are at identical pole number and
smaller radius considerably smaller than on the outside stator.
Thus, the space conditions are especially unfavorable for the
inside stator, entailing problems in the feed line design, winding
structure and assembly of the inside stator.
SUMMARY OF THE INVENTION
The problem underlying the invention consists in improving the
winding structure and the excitation of an electrical machine of
the initially named category to the effect that the line routing,
heat removal and assembly will be facilitated.
This problem is solved in that the excitation of the stator is
concentrated in a sole annular winding extending in peripheral
direction and in that this sole annular winding is accommodated
only in one of the two stator halves. The other stator half thus
remains void of an annular winding and, thus, magnetically
inactive. This stator half forms thus a magnetic back circuit
between the two permanent magnet rows on the pole structure of the
rotor. This measure entails a significant simplification of the
winding structure on the motor and a considerably simplified
assembly, in conjunction with elevated operational safety,
specifically as regards the insulation resistance in view of the
heat load to be expected.
In one embodiment of the invention, the sole annular winding is
disposed in the outside stator, allowing the inside stator to
remain void of a winding. The armature elements of the no-winding
stator part may be fashioned as laminated back circuit elements,
specifically as C-cores, and arranged in the peripheral direction
at a spacing corresponding to twice the pole pitch on the pole
structure of the rotor. The armature elements of the stator part
accommodating the annular winding may be fashioned as well as
C-cores which embrace the annular winding in U-shaped fashion on
three sides. The rotor may feature two pole structures which are
arranged symmetrically on both sides of the central plate, with the
two pertaining stators having a structure such that the sole
annular windings are always arranged in the same stator part, i.e.,
on the inside stator or preferably on the outside stator. This
measure assures a quiet non-vibrating running of the motor.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention will be described hereafter with the
aid of the drawing, which shows in
FIG. 1, a schematic longitudinal section through the electrical
machine;
FIG. 2, a schematic view of the rotor pole structure and of the
stator elements embracing them.
DETAILED DESCRIPTION OF THE INVENTION
The machine illustrated schematically in section in FIG. 1
comprises a stator housing 1 in which a rotor 2 with its shaft 3 is
rotatably mounted. The rotor consists of a central disk 4 on the
radially outer area of which there are two pole structures 12
arranged, symmetrically toward both sides and coaxially to the axis
of rotation of the shaft 3. These pole structures are comprised of
permanent magnets 13 which in two rows, in peripheral direction and
side by side, are alternately polarized and adjacent to soft iron
elements 14, with all parts being separated from each other by
electrically and magnetically nonconductive insulating layer 15
(FIG. 2), which is, preferably comprised of plastic. Embedded in
plastic, the disk 4 forms with the pole structure 12, the magnets
13 and soft iron elements 14 (illustrated in FIG. 2) a rotary body
reinforced in itself. Separated by an air gap 11, each of the pole
structures 12 is opposed by a stator assembly 5 consisting of a
radially outer outside stator 6 and a radially inner inside stator
7. Each outside stator 6 is comprised of a plurality of U-shaped
armature elements 9 whose open shanks oppose the permanent magnet
13 of the pole structure 12 of the rotor. Contained within each
outside stator 6 of each respective stator assembly 5 surrounded on
three sides by each respective armature element 9 is an armature or
annular winding 8 extending in peripheral direction. The inside
stator 7 is void of an annular winding and merely forms the
magnetic back circuit for stator excitation between the permanent
magnets 13 on the radially inner side, namely in a radial plane
(transversal flow principle).
Armature winding 8 is disposed only in one of the outside stator 6
and inside stator 7, the other of the outside stator 6 and inside
stator 7 being void of armature winding 8.
FIG. 2 shows schematically and in extended position a section of
one pole structure 12 of the rotor and the surrounding stator parts
6, 7. Visible are the two rows of permanent magnets 13 and soft
iron elements 14 which are arranged one behind the other and
combined by a magnetically and electrically nonconductive
insulating layer 15 in peripheral direction (FIG. 2). The permanent
magnets 13 of the one row, as compared to those of the other row,
are poled in different direction, creating a magnetic flux
direction according to arrow P. The two rows of permanent magnets
13 with soft iron elements 14 are separated from each other also
crosswise to their peripheral direction by magnetically and
electrically nonconductive insulating layer 15 (FIG. 1), preferably
plastic, but nonetheless connected with one another in load-bearing
fashion.
Also evident is that the outside stator 6 features soft iron
armature elements 9 which in peripheral direction are arranged
spaced from one another a distance 2T. The armature elements 9 are
fashioned as C-cores 10, i.e., are laminated. The same is true for
the armature elements of the inside stator 7, which are arranged
radially inside the pole structure 12, as illustrated in FIG. 1.
The armature elements 9 of the out-side stator are peripherally
offset by the pole pitch T relative to the armature elements of the
inside stator. The pole pitch T is given by the thickness of the
permanent magnets 13 and of the soft iron elements 14 including
each respective magnetically and electrically nonconductive
insulating layer 15. Also the armature elements of the inside
stator 7 are peripherally spaced by twice the pole pitch T, which
with the smaller radius of the armature elements on the inside
stator corresponds to a smaller absolute value of the spaces.
Therefore, the annular winding 8 is favorably arranged on the
outside stator 6, with the electrical lead 16 to this annular
winding preferably being routed between the armature elements 9 in
the radially outer area. In this way it is possible to design the
machine with smaller values for the pole pitch T and, thereby,
generate high power densities. Nonetheless, this measure avoids
assembly difficulties, a complex winding structure for the inside
stator and high thermal load.
* * * * *